In a typical turboprop engine, the propeller rotates in only one direction and the gearbox is designed to handle the associated reacted propeller loads accordingly, in addition to transmitting the driving power. However, because the gas turbine direction is generally fixed the propeller loads are somewhat asymmetric, and the gearbox design will vary depending on which direction the propeller is intended to rotate. Thus, if a gas turbine manufacturer wishes to provide a generic gas turbine engine capable or spinning a propeller in either direction depending on the customer's preference, two different gearbox designs must be available. Providing two gearboxes, however, increases the costs of production, inventory, etc. and, accordingly, there is a need for an improved gas turbine gearbox design adapted to drive a propeller either direction.